Kinetic, thermodynamic and structural studies of pig heart mitochondrial and supernatant (cytoplasmic) enzymes are to be continued. Emphasis is to be placed on ascertaining the significance of homopolymeric structure of the two dimeric enzymes. Comparative studies of the two enzymes will be used to identify properties which may relate to their unique biochemical functions, including possible regulatory aspects of the problem. BIBLIOGRAPHIC REFERENCE: Kimball and Wolfe, In Press, Archives of Biochem and Biophys. 1977 "Malate Dehydrogenase: A Higher Molecular Weight Form Produced by Freeze-Thaw Treatment of Pig Heart Supernatant Enzyme."